CVE-2018-4433 in tvOS
Summary
by MITRE • 10/28/2020
A configuration issue was addressed with additional restrictions. This issue is fixed in macOS Mojave 10.14.4, Security Update 2019-002 High Sierra, Security Update 2019-002 Sierra, watchOS 5, iOS 12, tvOS 12, macOS Mojave 10.14. A malicious application may be able to modify protected parts of the file system.
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Analysis
by VulDB Data Team • 11/27/2020
This vulnerability represents a critical configuration flaw that allowed unauthorized modification of protected file system components across multiple Apple operating systems. The issue stems from insufficient access controls and restrictive permissions that failed to properly isolate critical system directories from malicious applications. The vulnerability affects macOS Mojave 10.14, iOS 12, tvOS 12, watchOS 5, and older versions of macOS High Sierra and Sierra, indicating a widespread impact across Apple's ecosystem. The root cause lies in the improper enforcement of system integrity protection mechanisms that should have prevented malicious applications from accessing or modifying protected file system areas.
The technical exploitation of this vulnerability enables a malicious application to bypass normal file system restrictions and modify protected system components. This configuration issue essentially created a pathway for privilege escalation attacks where ordinary applications could gain elevated access to critical system files and directories. The flaw represents a failure in Apple's system integrity protection framework, allowing unauthorized modifications to system-critical areas that should remain protected from user-space applications. This type of vulnerability directly impacts the principle of least privilege and can lead to complete system compromise when exploited by adversaries.
The operational impact of this vulnerability extends beyond simple file system modifications to encompass potential system instability, data corruption, and complete system compromise. Attackers could leverage this weakness to install persistent backdoors, modify system binaries, or corrupt critical system files that maintain operating system integrity. The vulnerability creates a persistent threat vector that could be exploited by malware or advanced persistent threat actors to establish footholds within Apple environments. This type of flaw particularly affects enterprise environments where macOS systems are deployed and managed, as it could allow attackers to evade standard security controls and maintain long-term access.
Security mitigations for this vulnerability involve applying the respective security updates released by Apple, including macOS Mojave 10.14.4, Security Update 2019-002 for High Sierra, Security Update 2019-002 for Sierra, and corresponding updates for iOS, tvOS, and watchOS. Organizations should prioritize immediate deployment of these patches across all affected systems to remediate the configuration issue. Additional security measures include implementing application whitelisting policies, monitoring for unauthorized system modifications, and maintaining comprehensive system integrity monitoring. This vulnerability aligns with CWE-276 which addresses improper file permissions and access control issues, and relates to ATT&CK technique T1059 which covers command and scripting interpreter usage for persistence and privilege escalation.
The fix implemented by Apple addresses the underlying configuration issue through enhanced access controls and stricter enforcement of system integrity protection mechanisms. The security updates modify the permission models and access restrictions for protected file system areas, ensuring that only authorized system processes can modify critical components. This remediation strengthens the overall security posture by closing the access path that malicious applications previously exploited. Organizations should verify patch compliance through automated inventory management systems and ensure that all endpoints have received the appropriate security updates to prevent exploitation of this vulnerability. The vulnerability demonstrates the importance of maintaining up-to-date security configurations and proper system integrity protection in preventing unauthorized modifications to critical system components.